Beauty is full of buzzwords, but which ingredients truly deliver? Welcome to Ingredient Lab, your guide to the science behind the formulas. In this edition, we focus on a powerhouse active that’s made its way into countless skincare routines.
Review the ingredients of your skincare staples. Chances are, at least one product contains ascorbic acid (AA)—better known as vitamin C. While new star ingredients cycle in and out of people’s beauty shelves, vitamin C has quietly held its ground for years.
Still, despite its science-backed reputation for brightening and protecting the skin, vitamin C remains one of the most misunderstood actives. Can it cause irritation? When does it become unstable? And how do you use it to get real results? We break down the facts behind an ingredient that’s everywhere but often misused.
Vitamin C, Explained
A type of nutrient, vitamin C is a water-soluble antioxidant that’s essential for growth, tissue repair, and overall health. Humans cannot naturally make vitamin C inside their bodies due to the absence of the enzyme L-glucono-gamma lactone oxidase. Unlike animals and plants, people must get it from outside sources, whether through food and oral supplements or by applying it to their skin.
Though vitamin C is naturally present in plants, extracting it from these sources is impractical for skincare. As an alternative, manufacturers rely on synthesized methods that start with glucose from starch-rich plants. The result? Pure, highly concentrated, stable, and scalable L-ascorbic acid.
“Vitamin C stands out as a key cosmeceutical in skincare,” says Dr. Gwendolyn Wong, a board-certified dermatologist and dermatopathologist at St Luke’s Medical Center. As a core skincare active, “it fights off free radicals [caused by sun exposure and pollution] that make skin age faster.”
Going Above and Beyond Brightening
Vitamin C is often synonymous with radiant skin, but its effects go deeper than surface-level glow. Repeated exposure to ultraviolet (UV) light creates oxidative stress that depletes vitamin C in the skin and triggers excess pigment production. By helping reduce the activity of tyrosinase (an enzyme involved in melanin formation), topical vitamin C slows excess pigment buildup, allowing dark spots to fade gradually and skin tone to appear more even over time.
Dr. Wong explains how AA’s benefits extend well beyond brightening. “It strengthens the skin barrier, helping it retain moisture more effectively. It also gives a little UV shield, though you still need [to apply] real sunscreen.” Thanks to its anti-inflammatory properties, vitamin C can help calm skin and support recovery from daily environmental stress, making it especially helpful for acne-prone or easily congested skin.
AA also plays a critical role in collagen production, supporting skin structure and elasticity. It helps protect existing collagen from breaking down too quickly, reinforcing vitamin C’s role as a long-term anti-aging ingredient. “This keeps skin firm and [reduces the appearance of] wrinkles, which makes it important for [maintaining healthy-looking] skin over time,” adds Wong.
Form and Substance
With multiple forms of vitamin C available today, how can you tell which one is right for you? Dr. Wong advises users to consider their skin type. “Go for the pure one if you want more power and [have no skin] issues. L-ascorbic acid, which is studied a lot, works really well, but it might irritate [sensitive skin]. Then, there are derivatives that are not as strong, but they stay stable longer and are easier on the skin.”
L-ascorbic acid has been synthesized in laboratories since 1933, but it only gained traction in skincare in the 1990s, when researchers such as Dr. Sheldon Pinnell developed formulas stable enough for topical use. Even so, it remains notoriously “unstable,” breaking down when exposed to air, light, heat, and water. Since it requires a very acidic environment to remain active, it is typically formulated as a low-pH, water-based serum.
Over the years, skincare formulators have developed vitamin C derivatives to improve stability without sacrificing its benefits. Magnesium ascorbyl phosphate (MAP) is a water-soluble form often recommended for sensitive or acne-prone skin. Once applied, MAP slowly converts to active vitamin C without creating a burning or stinging sensation.
Ascorbyl glucoside (AG), another water-soluble derivative, is popular for its slow-release action. By delivering vitamin C in a steady, sustained manner, the formula provides lasting antioxidant protection and continued collagen synthesis.
Tetrahexyldecyl ascorbate (THD) is a stable oil-soluble derivative of vitamin C. Since it can be used at neutral pH, it is commonly paired with nourishing oils and creams. The lipid-friendly structure allows it to integrate more easily into the skin, contributing to a brighter, more even complexion.
Form matters, but so does the system designed to protect it. Whether you opt for pure vitamin C or derivatives, choose formulations in airless, opaque packaging that slow oxidation and preserve potency.
Unlocking Vitamin C’s True Potential
Vitamin C shows up in countless skincare products. Serums are very popular since they’re lightweight and pair well with sunscreen, but creams provide intense moisture. For AA newbies, Wong suggests trying masks that “pack a big dose in a short time for that quick pick-me-up” and toners that “freshen things up and get your skin ready for the rest of your routine.”
When integrating vitamin C into your skincare routine, start small. Dr. Wong reminds users to “test on a small spot first. Use it in the morning [and apply] sunscreen after, since it helps against the sun and pollution. If your skin darkens during the day through makeup, it’s best that vitamin C be applied only at night.”
Check the label as different formulations can alter the antioxidant’s strength and effects. “The best concentration is 10 to 20 percent in a good product. People’s misconception is that if a product has a higher concentration, it’s more effective. They pick too strong a concentration or mix it with niacinamide or retinol, [which] causes redness or irritation,” explains Wong.
Aside from niacinamide and retinol, be wary of ingredients that don’t go well with vitamin C. Exfoliating acids (AHAs or BHAs), benzoyl peroxide, and copper peptides can rapidly oxidize vitamin C or destabilize pH balance. On the other hand, Wong says, “Adding vitamin E or ferulic acid makes [vitamin C] work better and last longer.” Vitamin E assists in strengthening AA’s antioxidant power while ferulic acid keeps the whole formula from falling apart.
Whichever you use, find products you can easily add to your routine and feel best on your skin. “If it’s not comfortable, you will not use it enough, and the results suffer,” says Wong.
Your Vitamin C Moment
Experience vitamin C’s long-lasting power. Here are suggestions worth adding to your skincare regimen.
VMV Illuminants+ Cleansing Cream
P1,500, The Beauty Edit Gallery at Spatio
The clarifying actives found in this pH-adjusted exfoliating cleanser help lighten and brighten skin.
Hello Glow Vitamin C Suncare Cream SPF 50
P401, The Beauty Edit Gallery at Spatio
This non-greasy sunscreen contains a triple vitabright complex that works hard to reduce dark spots.
Pure Culture Wild Algae Glow-Up Serum
P599, The Beauty Edit Gallery at Spatio
Got oily or combination-type skin? Zap acne and blemishes with this vitamin C-packed serum.
Popique Face Forward Multi-Complexion Pot
P399, The Beauty Edit Gallery at Spatio
The ascorbic acid and tocopheryl acetate (vitamin E) in this all-in-one buildable product effectively minimize redness and dark spots.
Discover more F-beauty brands at The Beauty Edit Gallery at Spatio, located on the 3/F of Opus Mall, Bridgetowne Destination Estate, Quezon City. An editorial-led retail concept—and the first-of-its-kind in the local scene—the gallery spotlights indie innovators, cult icons, and niche trailblazers shaping F-beauty today.
